Determine backup destination from RestoreSet transport flags on restore

The correct backup destination needs to be set to ensure the correct
include/exclude rules are applied during restore.

Also make sure to set the transport flags in the LocalTransport when the
cross-platform transfer parameter is enabled.

Flag: com.android.server.backup.enable_cross_platform_transfer
Bug: 432673356
Test: atest ActiveRestoreSessionTest
Test: manual testing

Change-Id: I16424a422f9aa31d85507abf929487d08970da10